Meet Andrew Ritchie for the first time, and take in what you see: a lean, middle-aged man, slightly dishevelled, with one leg of his brown corduroy trousers tucked into his sock.
You might guess that he is a slightly posh gardener who has just cycled back from his last landscaping project: he has something of the outdoor air about him. The tucked-in trouser leg gives him away as a cyclist.
And you would not be completely wrong. Yes, Andrew Ritchie used to be a landscape gardener. And yes, he's certainly a cyclist: each day, he pedals the six-and-a-bit miles from his home in South Kensington, west London to work on an unprepossessing industrial estate sitting in the lee of Junction 2 of the M4.
But Ritchie, 58, is more than just another cyclist. He is a self-confessed obsessive, someone who has devoted the past 30 years of his life to building the best portable bicycle in the world, a machine that is fun and efficient to ride but can be quickly folded into a package smaller than an average suitcase, carried up and down stairs, tucked behind a train seat or secreted under a desk.
And it is an obsession that has reaped rewards. Ritchie controls and runs Brompton Bicycle, one of only two volume manufacturers still making bikes in Britain. No, it will never be on the scale of a Raleigh, which in its heyday was producing a million frames a year and whose bikes are now imported. But since its inception, Brompton has made almost 100,000 of its distinctive 'folders'. It aims to produce nearly 14,000 in the coming year. It is a rarity - a British manufacturing success story.
Ritchie read engineering at Cambridge - 'of no relevance to making bikes,' he points out, 'metal-bashing didn't come into it'. He worked for a time in big industry, for Elliott Automation - later swallowed up by Marconi - and then as a programmer.
'But I had a taste for doing things on my own, and a friend and I thought there had to be money in selling pot plants. It didn't work out, but it did lead to a lot of interest in people having their gardens done, so we ended up doing indoor displays, maintaining gardens and doing landscaping. It was neither a success nor a catastrophe. It just broke even for five years.'
Then, in the mid-Seventies, Ritchie's father, a stockbroker, met an Australian, Bill Ingram, who was trying to raise some money for Bickerton, a British company which made the first genuinely portable folding bike - light, but rather rubbery to ride.
'My father said "Oh, my son would be interested in that." So poor old Bill Ingram had to waste an evening coming to see me. I thought the design left quite a lot wanting. That evening, after Bill had gone home, I started sketching out designs on scrappy bits of paper,' recalls Ritchie.
The obsession bit. Ritchie persuaded 10 friends to part with £100 each so that he could build a prototype. A year later, his first bike was complete. 'It was rideable and it worked, but it is something I'm deeply ashamed of as a piece of engineering.' Prototype numbers two and three followed, assembled in Ritchie's flat overlooking Brompton Oratory - hence the bike's name.
'It was quite a knife-and-fork business,' he says. 'The work went on in my bedroom in that flat, making a real mess with swarf and bits and pieces all over the place.'
Ritchie tried to license the design to a big manufacturer such as Raleigh - with no joy. But he persuaded 30 people to order bikes and pay in advance - '£250 a pop, which was quite a lot of money in those days. I ended up making 50 rather than just the 30, thinking that maybe there were another 20 people out there who would be interested in buying one.' Eventually, after 18 months, the bikes were delivered - and Ritchie sold all 50.
At the beginning of the Eighties, he raised £8,000 from shareholders. Over two years, Ritchie made 500 bikes.
'It was jolly hard work,' he says, 'There was me and one employee, who was doing all the brazing. It was hopelessly inefficient, but it broke even. So I thought I ought to try to raise some venture capital and get the thing going properly. My timing couldn't have been worse. The bicycle business in Britain was in decline. I never came across as a natural entrepreneur, and they're pretty wary of the inventor setting himself up as an entrepreneur as well. So that came to nought.'
But the late Julian Vereker, founder of Salisbury-based hi-fi maker Naim, agreed to guarantee a £40,000 overdraft and Ritchie persuaded his father and friends who had bought the pilot production to put in money: 'We raised £50,000 or so in equity, and we were off.'
Production proper started under a railway arch in Brentford in 1988. 'It was all quite nerve-racking. Everything that could go wrong did. When something went right, it was a cause for celebration. But from day one, when we started making bikes, we didn't have any stock. Everything we made, we sold. It was profitable from day one, too.'
Now, the company - based in a pukka factory rather than railway arches - exports around 60 per cent of its output. The biggest overseas market is Holland. 'Well, they are bike-mad,' he says, before correcting himself - 'not bike-mad, bike-sensible.' And, fulfilling Ritchie's dream, the Brompton is by common consent the best, most portable folding bike in the world.
'Private backing allowed me to be a perfectionist,' he says. 'In a way, I'm glad we didn't get a licensing deal with Raleigh. I'm not sure that the business would have survived. The bike probably would have been dumbed down and cheapened.'
And his obsession with quality helps explain why Brompton still manufactures in the UK. 'Yes, we make things in the UK, and in west London, which is one of the more expensive places,' he says. 'Rents and rates are more expensive, but that's only a small part of the equation. We have competitors, but price is not the issue.
'If we started manufacturing in the Far East, we could never be sure that rates of exchange or wage rates wouldn't catch up or there wouldn't be disruption of supplies, or the cost of shipping might go up.
'Including different colours, there are now 13 billion possible permutation of bike - different handlebars, gears, lighting, that sort of thing. We can make a particular bike on the spot tomorrow, which you couldn't do with Far East manufacturing.'
Brompton has been Ritchie's life: 'I have worked bloody hard. I've remained single. I haven't had a family - this is my family in a sense. I went through years in the doldrums as a thoroughly unmarriable chap - no income at all and obsessed with his project.' But now he's ready to take a back seat. 'I'm craving more time - to travel, play tennis garden, and just be. I hardly know my own house.'
He is looking for a way of enjoying the fruits of his success, giving up control in the hope that the company's culture is maintained.
'When I started, developing the product was a nice little puppy, if you like,' he says. 'Now, it has grown into a big dog and it's pulling me, rather than the other way around. The likely outcome is that I will cede control. The better the hands into which I can cede it, the happier I will be.'